Silver halide element containing merocyanine dyes with a 3-pyrrolinylalkyl group

ABSTRACT

Novel merocyanine dyes of which the acid nucleus, such as a rhodanine nucleus, has a 3-pyrrolinylalkyl group attached thereto. The dyes are spectral sensitizers for silver halide photographic emulsions and also increase the blue sensitivity of the silver halide. Intermediates for these dyes are novel cyanoalkyl-3-pyrrolines and aminoalkyl-3-pyrrolines.

United States Patent [191 Fumia, Jr. et al.

[ 51 Feh.27,1973

[75] Inventors: Arthur Fumia, Jr.; Donald W.

Heseltine, both of Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Oct. 23, 1970 [21] Appl. No.: 83,621

[52] US. Cl. ..96/127, 96/139, 96/140, 260/240.1, 260/313.1

[51] Int. Cl. ..G03c l/l0 [58] Field of Search ..96/l27, 139, 140

[56] References Cited UNITED STATES PATENTS 2,575,018 11/1951 Keyes eta1. ..96/l40 2,839,404 6/1958 Knott 3,384,486 5/1968 Taber et a1.3,582,348 6/1971 Haseltine et al ..96/107 Primary ExaminerJ. TravisBrown Att0rney-William H. .l. Kline, James R. Frederick and Ogden H.Webster [57] ABSTRACT Novel merocyanine dyes of which the acid nucleus,such as a rhodanine nucleus, has a 3-pyrro1inyla1ky1 group attachedthereto. The dyes are spectral sensitizers for silver halidephotographic emulsions and also increase the blue sensitivity of thesilver halide. Intermediates for these dyes are novel cyanoalkyl-3-pyrrolines and aminoalkyl-3-pyrrolines.

7 Claims, No Drawings This invention relates to photographic sensitizingdyes and to intermediates for such dyes and more particularly tomerocyanine dyes having an acid nucleus with a 3-pyrrolinyl alkyl groupattached thereto and to photographic silver halide elements containingsuch dyes.

Many merocyanine dyes are excellent spectral sensitizers for negativesilver halide emulsions. A problem with the merocyanines, however, hasbeen their insolubility. This inherent insolubility of merocyanines hasbeen improved by the introduction of dialkylaminoalkyl substituents, asin the following compound:

' merocyanine dyes of which the acidic nucleus is a rhodanine oranalogous group and has as a nitrogen substituent a 3-pyrrolinylalkylgroup. The novel dyes of the invention can be represented as follows:

In the formula:

R represents an alkyl group having from one to 18 carbon atoms (e.g.,methyl, sulfoethyl, hydroxyethyl, hydroxypropyl, sulfobutyl,carboxybutyl, hexyl, octyl, dodecyl, etc.) or an aryl group of six to 12carbon atoms (e.g., phenyl, sulfophenyl, carboxyphenyl, tolyl, etc.).

'2 represents the nonmetallic atoms required to complete a heterocyclicnucleus having from five to six atoms in the heterocyclic ring (whichcan contain a second hetero atom, e.g., a hetero oxygen, sulfur orselenium atom, or a second nitrogen atom) such as: a thiazole nucleus(e.g., thiazole, 4-methylthiazole, 4- phenylthiazole,fi-methylthiaz'ole, 4,5-dimethyithiazole, 4,5-diphenylthiazole, etc.); abenzothiazole nucleus (e.g., benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 4-methylbenzothiazole, 6- methylbenzothiazole,S-bromobenzothiazole, 5- methoxybenzothiazole, 6-iodobenzothiazole, 5,6-

' dimethoirybenzothiazole, etc.); a naphthothiazole nucleus (e.g.,a-naphthothiazole, fl-naphthothiazole, 5-

methoxy-Bmaphthothiazole, 8-ethoxy-anaphthothiazolefl B-naphthothiazole,etc.); a thianaphtheno-7',6',4,5-thiazole nucleus (e.g., ,4-methoxythianaphthenofl',6,4,5-thiazole, etc.); an oxazole nucleus (e.g.,4-methyloxazole, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole,4-ethyloxazole, 4-,5 -diethyloxazole, etc.); a benzoxazole nucleus(e.g., benzoxazole, 5-chlorobenzoxazole, S-methylbenzoxazole,-phenylbenzoxazole, -methylbenzoxazole, 5,6-

dimethylbenzoxazole, 4,6-dimethyibenzoxazole, 5- ethoxybenzoxazole,5,6-dichlorobenzoxazole, 5- hydroxybenzoxazole, etc.); a naphthoxazolenucleus (e.g., a-naphthoirazole, B naphthoxazole, 3,13- naphthoxazole,etc.); a selenazole nucleus (e.g., 4- methylse lenazole,4-phenylselenazole, etc.); a benzoselenazole nucleus (e.g.,benzoselenazole, 5- chlorobenzoselenazole, 6-methoxybenzoselenazole, 5-hydroxybenzoselenazole, a tetrahydrobenzoselenazole, etc.); anaphthoselenazole nucleus (e.g., anaphthoselenazole,B-naphthoselenazole, 3,3- naphthoselenazole, etc.); a thiazoline nucleus(e.g., thiazoline, 4-methylthiazoline, etc.); a 2-pyridine nucleus(e.g., Z-pyridine, S-methyl-Z-pyridine, etc.); a 4-pyridine nucleus(e.g., 4-pyridine, 3-methyl-4- pyridine, etc.); a 2-quinoline nucleus(e.g., Z-quinoline, 3-methyl-2-quinoline, S-ethyl-Z-quinoline,6-chloro-2- quinoline, 8-chloro-2-quinoline, 4-methoxy-2-quinoline,8-hydroxy-2-quinoline, etc.); a 4-quinoline nucleus (e.g., 4-quinoline,5-methyl-4-quinoline, 7- methyl-4-quinoline, 8-chloro-4-quinoline,etc.); a 1- isoquinoline nucleus (e.g.,lisoquinoline,3,4-dihydrol-isoquinoline, etc.); a 3-isoquinoline nucleus(e.g., 3- isoquinoline, etc.); a 3,3-dialkylindolenine nucleus (e.g.,3,3-dimethylindolenine, 3,3,S-trimethylindolenine,3,3,7-trimethylindolenine, etc.); an imidazole nucleus (e.g., imidazole,l-alkylimidazole, l-alkyl-4- phenylimidazole,1-alkyl-4,5-dimethylimidazole, etc.); a benzimidazole nucleus (e.g.,benzimidazole, l-alkylbenzimidazole, l-arylbenzimidazole, 5 ,6-dichlorobenzimidazole, etc.); or a naphthimidazole nucleus (e.g.,l-alkyl-a-naphthimidazole, l-aryl-flnaphthimidazole,l-alkyl-S-methoxy-B- naphthimidazole, etc.

L and L which can be the sameor different, represent methine groups suchas CE, where E represents hydrogen; a lower alkyl such as methyl, butyl,etc.; an aryl group such as tolyl, napthyl, etc.; or a heterocyclicgroup such as Z-thienyl, 2-pyrryl, 3-pyrryl, 2-indolyl, 3-indolyl,3-pyridyl,4-pyridyi or etc.; such that not more than one of L and Lcontains an E group that is other than hydrogen.

n and m, which can be the same or different, each represents an integerfrom 1 to 3; y is an integer from 2 to 5; and

X represents -S--, 0, -Se, or -NR,-, where R is hydrogen or an alkyl oraryl group as defined above for R.

I The novel cyanoalkyl-Ei-pyrroline and aminoalkyl-3- pyrrolineintermediate compounds of the invention can be represented as follows:

I N( CHzh-NH:

where y is an integer from 2 to 5.

These compounds can be prepared by reaction of 3- pyrroline with ahalogen-substituted nitrile of the formula X--(CH ,--CN, where X ischlorine, iodine or bromine, such as chloracetonitrile,3-iodopropionitrile, 4-bromobutyronitrile, or 5-iodopentanonitrile. Forthis reaction, the halonitrile is added with stirring and, if desired,with heating, to an equimolar amount of 3-pyrroline in a hydrocarbonsolvent such as benzene to form the acid salt of the desiredcyanoalkyl-3-pyrroline compound. The precipitated acid salt is thendissolved in water and treated with a base stronger than pyrroline, forexample, a tertiary amine such as triethylamine, to obtain the desiredcyanoalkyl-3-pyrroline compound II. The latter is then chemicallyreduced, e.g., by reaction with lithium aluminum hydride in an ethersolvent, to the corresponding primary amine. The amine is reacted in analkaline solution with bis(carboxymethyl) trithiocarbonate to obtain anN-substituted rhodanine compound, which is subsequently condensed with abasic nucleus-supplying compound to form the desired merocyanine dye.

The series of reactions for preparing the intermediate compounds can beillustrated as follows:

base

As an alternative for the preparation of such compounds in which y=3,the intermediate cyanoalkyl-3- pyrroline compound II can be obtained bythe reaction of 3-pyrroline with acrylonitrile, the reaction beingrepresented as follows:

+CH1=CHCN NCHrCHaCN Q II II By methods well-known in the art, the novelintermediate aminoalkyl-3-pyrroline compounds [II can be used to prepareother novel solubilized ketomethylene compounds, which like the novelcompound IV, are useful as methine dye intermediates by reactions suchas disclosed hereinafter; such other ketomethylene compounds including:

Merocyanine dyes of the invention in which n is 1 can be obtained byreacting the N-substituted rhodanine compound with a cyclammonium saltof the formula where R, Z and n have the meanings previously given, Q isan anion such as chloride, bromide, iodide, perchlorate or the like andR is an alkyl group, e.g., methyl, ethyl, benzyl, etc. or an aryl group,e.g., phenyl, p-chlorophenyl, tolyl, etc. This condensation reaction isadvantageously carried out by heating the reactants under reflux in aninert diluent such as methanol, ethanol, butanol, dimethylformamide,acetone, l,4- dioxane or the like with a basic condensing agent, e.g., atrialkylamine such as triethylamine, a dialkylaniline such asN,N-dimethylaniline, or a heterocyclic tertiary amine, such as pyridine,quinoline, etc.

The dyes of the invention in which n is 2 to 3 can be prepared bycondensing with the N-substituted rhodanine compound IV or its S, 0, Seor NR analogs, a cyclammonium salt of the formula where R, Z, O, n, Land L and m have the meanings previously given and J represents a group,aSR group or a halogen atom (e.g., chlorine, bromine, etc.), R,represents the hydrogen atom, an alkyl group (e.g., methyl, ethyl,etc.), or the acyl group of a carboxylic acid (e.g., acetyl, propionyl,etc.), R represents an aryl group (e.g., phenyl, tolyl, etc.), or R, andR together represent the nonmetallic atoms necessary to complete aheterocyclic nucleus (e.g., a piperidino, morpholino, etc. nucleus), andR represents a lower alkyl group. The condensation is advantageouslycarried out in the presence of a basic condensing agent, in an inertsolvent and at an elevated temperature as described previously.

Our optical sensitizing dyes are used to advantage to sensitize silverhalides, e.g., silver chloride, silver bromide, silver iodide, silverchlorobromide, silver bromoiodide, silver chlorobromoiodide, etc., whichhave been dispersed in any hydrophilic colloid known to be satisfactoryfor making light-sensitive photographic emulsions. Useful hydrophiliccolloids include natural materials, e.g., gelatin, albumin, agar-agar,gum arabic, alginic acid, etc., and synthetic materials, e.g., polyvinylalcohol, polyvinyl pyrrolidone, cellulose ethers, partially hydrolyzedcellulose acetate, etc.

The concentrations of our dyes in the emulsions can vary widely, i.e.,from about 5 to 100 mg. per liter of flowable emulsion. The specificconcentration will depend upon the dye, the type of light-sensitivematerial in the emulsion and the particular effects desired. The mostadvantageous dye concentration for any given emulsion can be readilydetermined by making the concentration series and observationscustomarily used in the art of emulsion making.

Our dyes are readily soluble in water in the presence of one equivalentof acid. The hydrophilic colloid-silver halide emulsion is sensitized toadvantage by adding the appropriate amount of dye in aqueous solution tothe emulsion with intimate mixing to insure uniform distribution. Any ofthe other methods customarily used in the art can be used forincorporating our dyes. For example, the dyes can be incorporated bybathing a photographic element coated with the emulsion, in a solutionof the dye.

Photographic silver halide emulsions, such as those listed above,containing the sensitizing dyes of our invention can also contain suchaddenda as chemical sensitizers, e.g., sulfur sensitizers (e.g., allylthiocarbamide, thiourea, allylisothiocyanate, cystine, etc.) variousgold compounds (e.g., potassium chloraurate, auric trichloride, etc.)(see U. S. Pat. Nos. 2,540,085; 2,597,856 and 2,597,915), variouspalladium compounds such as palladium chloride (U. S. Pat. No.2,540,086), potassium chloropalladate (U. S. Pat. No.

No. 771,380 filed Aug. 29, 1947 (now U. S. Pat. No. 2,640,776), etc.; ormixtures of such addenda. Dispersing agents for color couplers, such asthose set forth in U. S. Pat. Nos. 2,322,027 and 2,304,940 can 5 also beemployed in the above-described emulsions.

EXAMPLE 1 20 5 3-Ethyl-2-benzothiazolinylidene )-3- 3-( 3-pyrrolin-2,598,079) etc., or mixtures of such sensitizers; an- 5 tifoggants suchas ammonium chloroplatinate (U. S. Pat. No. 2,566,245), ammoniumchloroplatinite (U. S. Pat. No. 2,566,263), benzotriazole,nitrobenzimidazole, 5-nitroindazole, benzidine, mercaptans, etc. (seeMees The Theory of the Photo- 60 l-yl )propyl]rhodanine s N(CHQ);- i s 03-[ 3-( 3-Pyrrolinl -yl)propyl]rhodanine perchlorate (1.7 g.),3-ethyl-2-phenylthiobenzothiazolium iodide (2.0 g.) and piperidine (1.5ml.) are dissolved in ethanol (15 ml.) and heated at reflux for 5minutes. 5 After chilling, the crude dye is collected on a filter andthen recrystallized from ethanol containing a small amount ofpiperidine. The yield of purified dye is 0.6 g. (30%), mp. l52-lS3C.

EXAMPLE 2 5-[(3-Ethyl-2-benzothiazolinylidene)ethylidene1-3-[3-(3-pyrrolin-1-yl)propyl]rhodanine 3-[ 3-( 3-Pyrrolinl -yl )propylrhodanine perchlorate 1 .7 g.2-(2-acetanilidovinyl)-3-ethylbenzothiazolium 5 iodide (2.3 g.), andpiperidine (1.5 ml.) are dissolved in N,N-dimethylacetamide (10 ml.) andheated at a gentle reflux for 5 minutes. The hot reaction mixture isthen diluted to approximately 250 ml. with boiling methanol. Afterstanding at room temperature for 45 minutes, the dye is collected on afilter and dried. The

yield is 1.3 g. (62%), m.p.=188-l89C. dec.

EXAMPLE 3 5 5-[(3-Ethyl-2-benzoxazolinylidene )ethylidene]-3-[3-(3-pyrrolinl -yl)propyl] rhodanine 3-[3-(3-Pyrrolin-l-yl)propyl]rhodanineperchlorate 1.7 g.), 2-( 2-acetanilidovinyl)-3-ethylbenzoxazolium iodide(2.2 g.), and triethylamine (2.1 ml.) are dissolved in ethanol (15 ml.)and heated at reflux for minutes. Piperidine (1.0 ml.) is added and,after chilling, the crude dye is collected on a filter and dried. Thecrude yield is 1.7 g. (85%). After one recrystallization from ethanol,the yield of purified dye is 1.3 g. (65%), m.p.=201-202C. dec.

EXAMPLE 4 5-[ 3-Methyl-2-thiazolidinylidene )ethylidene -3-[ 3-(3-pyrrolin-l -yl )propyl rhodanine 3-[ 3-( 3-Pyrrolinl-yl)propyl]rhodanine perchlorate (1.7 g.),2-(2-anilinovinyl)-3-methyl-2-thiazolinium iodide (1.7 g.), aceticanhydride (1.0 ml.), and triethylamine (2.5 ml.) are dissolved inethanol (15 ml.) and heated at reflux for 5 minutes. Piperidine (1.0ml.) is added and, after chilling, the solid is collected on a filterand then recrystallized from methanol containing a small amount ofpiperidine. The yield of purified dye is 1.2 g. (67%), m.p.=l33-134C.dec. 200BHC.

EXAMPLE 5 5-[( 1-Methylnaphth0[ l,2-d]thiazolin-2-ylidene)ethylidene]-3-[ 3 3-pyrrolinl -yl)propyl]rhodanine2-Formylmethylene-1-methylnaphtho[ l ,2- d]thiazoline (1.2 g.),3-[3-(3-pyrrolin-l-yl)propyl] rhodanine perchlorate (1.7 g.), andpiperidine (1.0 ml.) are dissolved in N,N-dimethylacetamide ml.) andheated at a gentle reflux for 5 minutes. The hot reaction mixture isthen diluted to approximately 250 ml. with boiling methanol. Afterstanding at room temperature for 30 minutes, the dye is collected on afilter and dried. The yield is 0.8 g. (35%), m.p.=229230C. dec.

Example 6 illustrates the preparation of a novel cyanoalkyl-3-pyrrolineintermediate compound of the 5 invention.

EXAMPLE 6 l-(2-Cyanoethyl)-3-pyrroline 3-Pyrroline (69.1 g.) is addeddropwise to acrylonitrile (80.0 g.) and the mixture allowed to stir atroom temperature for 2-3/4 hours. The mixture is then distilled in vacuoto yield 107.7 g. (88%) of product, b.p.=86B-88C/3.0 mm Hg.

Example 7 illustrates the preparation of a novel aminoalkyl-3-pyrrolineintermediate compound of the invention.

EXAMPLE 7 1-( 3-Aminopropyl)-3-pyrroline This compound is obtained by alithium aluminum hydride reduction of the compound described in Example6, 24.4 g. of the compound being added to 1 1.4 g. of lithium aluminumhydride in 450 ml. of ether at 25C., with stirring for 20 hours. Theyield is 65-70%, b.p.=64C/3.0 mm Hg.

Example 8 illustrates the preparation of a novel N- substitutedrhodanine compound of the invention.

EXAMPLE 8 3-[ 3-( 3-Pyrrolin- 1 -yl )propyllrhodanine perchlorate To asolution of sodium carbonate (1 l l g.) in water (250 ml.) is addedbis(carboxymethyl) trithiocarbonate (22.6 g.) in small portions.l-(3-Aminopropyl)- 3-pyrroline (14.0 g.) is then added and the mixtureheated on a steam bath for 2 hours with stirring. The mixture is thenmade strongly acidic with concentrated hydrochloric acid. After heatingon a steam bath for an additional one-half hour, an aqueous solution ofsodium perchlorate (18.0 g.) is added. After cooling, the mixture isfound to be neutral and more concentrated hydrochloric acid is added tomake the mixture strongly acidic. The stirred mixture is then heated ona steam bath for an additional 1% hours and then chilled. The water isthen decanted and the viscous residue stirred with ether to formcrystals. The solid is collected on a filter and dried. The yield is14.3 g. (42 m.p.=1.20B(-121C.

Example 9 illustrates the preparation and testing of novel photographicemulsions and elements of the invention and provides a comparison of thephotographic properties of the dyes of Examples 1-5 with anothermerocyanine dye, referred to hereinafter as Dye A.

EXAMPLE 9 Photographic Utility The dyes of Examples l-5, dissolved insuitable solvents, are added to separate portions of a monodispersedsulfur and gold sensitized, 0.2 pm. silver b ronioiodide gelatineemulsion contaihihg fj mole percent iodide at the concentrationsindicated below. After digestion at 40C. for 10 minutes, the emulsionsare coated-at a coverage of 100 mg. of Ag/ft on acellulose acetate filmsupport. A sample of each coating is exposed on an Eastman lBsensitometer and to a wedge spectrograph, processed for 6 minutes at20C. in a developer similar to Kodak D-l9 developer, fixed, washed anddried. Also tested under the same conditions is Dye A, of the followingstructure, which is like the novel dye of Example 2, except that it hasan ethyl group instead of 3-pyrrolinyl attached to the nitrogen of therhodanine nucleus.

3-Ethyl-2 3-ethyl-2-benzothiazolinylidene )ethylidenelrhodanine Thefollowing table lists the results of the photo- The 365 line exposure ofunsensitized control-=1 00 The spectral sensitization data of the abovetable (maximum wavelength sensitization and range) demonstrate that thedyes of the present invention spectrally sensitize silver halideemulsions to light of longer wavelength than the intrinsic bluesensitivity of the emulsion. The Relative Speed column of the table alsoshows the unexpected increase in blue sensitivity for Dyes 1-5 ascompared with the unsensitized control and Dye A.

We do not wish to be bound by theoretical explanations of these valuableresults. A possible explanation, however, is that the introduction intoa ketomethylene nucleus, such as a rhodanine nucleus, of a3-pyrrolinylalkyl substituent and the position of the double bond in theheterocyclic ring of this substituent not only provides solubility inhydrophilic solvents but also as 1M 4;

unexpectedly improves the positive hole-trapping ability of theresulting merocyanine dyes.

Certain of the novel compounds of the invention, such as the substitutedrhodanine compound of Example 8 are conveniently prepared and used as asalt, so

- when referred to in the claims, the salts of such compounds are alsomeant to be included.

The invention has been described indetail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention.

We claim:

sensitizing amount of a dye of the formula:

wherein:

R represents an alkyl group of one to 18 carbon atoms or an aryl groupof six to 12 carbon atoms;

Z represents the nonmetallic atoms required to complete a heterocyclicnucleus selected from the group consisting of a thiazole nucleus, a

benzothiazole nucleus, a naphthothiazole nucleus,

an oxazole nucleus, a benzoxazole nucleus, a

naphthoxazole nucleus, a selenazole nucleus, 21 benzoselenazole nucleus,a naphthoselenazole nucleus, a thiazoline nucleus, a Z-pyridine nucleus,

a 4-pyridine nucleus, a Z-quinoline nucleus, a 4- quinoline nucleus, al-isoquinoline nucleus, a 3,3- dialkylindolenine nucleus, an imidazolenucleus, a benzimidazole nucleus and a naphthimidazole Nucleus;

L and L, represent methine groups;

n and m represent integers from 1 to 3;

X represents sulfur, oxygen, selenium or NR where R is hydrogen or analkyl or aryl group as defined for R; and

y is an integer from 2 to 5.

2. A photographic element according to claim 1,

\ wherein X is sulfur and y is 3.

3. A photographic element according to claim 1 in O which said dye is ofthe formula 4. A photographic element according to claim 1 in whichsaiddye is of the formula 5. A photographic element according to claim 1in which said dye is of the formula 6. A photographic element accordingto claim 1 in which said dye is of the formula

2. A photographic element according to claim 1, wherein X is sulfur andy is
 3. 3. A photographic element according to claim 1 in which said dyeis of the formula
 4. A photographic element according to claim 1 inwhich said dye is of the formula
 5. A photographic element according toclaim 1 in which said dye is of the formula
 6. A photographic elementaccording to claim 1 in which said dye is of the formula
 7. Aphotographic element according to claim 1 in which said dye is of theformula